1. Field of the Disclosure
The present disclosure relates to the field of contact detection for measurement sensors. More particularly, the present disclosure relates to identifying when, based on contact detection, measurement of a workpiece should be taken by a measurement sensor.
2. Background Information
Currently, coordinate measuring machines (CMMs) are used to measure the coordinates of a workpiece. A set of workpiece coordinates in a 2 or 3 dimensional space can be used to model the workpiece. A probe and workpiece are moved relatively towards each other, and a contact detector detects when the probe contacts the workpiece. Contact detectors are used to control the timing of when measurement sensors take measure of the coordinates of the probe, and may detect contact characteristics such as deflection of the probe, as the probe contacts and pushes into or against the workpiece. The probe may probe the workpiece from many different angles and at many different positions, so that the coordinates are taken many times. For consistency between measurements of the coordinates, characteristic thresholds may be used so as to consistently know when to take the coordinates. For example, a threshold amount of deflection in one or more dimensions may be used to determine when to measure the coordinates.
Additionally, the contact detection characteristics may be measured at a rapid pace, such as 1000 or 2000 times per second, as the probe is engaged in a single probing motion to probe the workpiece. Ultimately, for a single probing motion against a single point of the workpiece, only a single coordinate measurement may be desired, such as when contact deflection characteristics of the probe is at or closest to a predetermined threshold amount. By knowing the exact coordinates of the probe at times when the same threshold amount of deflection occurs, the shape of the workpiece can be accurately determined and modeled.